ISO 18172-1:2007 specifies minimum requirements concerning material, design, construction and workmanship, manufacturing processes and testing of refillable transportable welded stainless steel gas cylinders, of water capacities from 0,5 l up to and including 500 l, for compressed, liquefied and dissolved gases. ISO 18172-1:2007 is applicable only to cylinders manufactured from stainless steels with test pressures up to 6 MPa (60 bar).
If required, transportable large cylinders of water capacity above 150 l and up to 500 l may be manufactured and certified to ISO 18172-1:2007, providing that handling facilities are provided.